Assessing spatial and temporal variations in individual exposures to airborne particulate matter components that are representative of key local sources like diesel traffic is critical for advancing our understanding of the health effects of urban air pollution. Current methods of exposure assessment are too cumbersome, noisy and labor-intensive, and do not provide near-real time measurements of key analytes. We propose to develop and test a miniature (palm size), quiet, rechargeable personal sampler that will (1) log in near real-time, time- and space-resolved concentrations of black carbon (BC), (2) collect and archive time- and space-resolved PM samples for later laboratory analysis, (3) have one additional channel for use in chemo-optical analysis of a relevant gas or vapor, such as ozone, and (4) log location and activity data. Our design goals for size, power, cost and quietness will permit wide use on most individuals, including young children, without disruption of normal activities. BC will be measured via an internal subminiature optical adsorption analysis of deposited particles. Spatial information will be provided by a miniature global position sensor (GPS) for outdoor locations and small home-/work-/car- placed radio beacons for key indoor locations. The unit will archive multiple time- and space-resolved particulate samples, for lab analysis via mass spectrometric and single particle techniques, to identify temporal-spatial patterns of exposure to particle sources and to a wide range of trace metals. The programmable miniature "smart" personal monitoring system will have the flexibility to be used in a wide range of sampling designs to assess spatial and temporal patterns of expsoure. Development milestones will include designing, building and testing 3 progressively more advanced versions of the sampler. Version 1 will integrate a GPS sensor, but will lack real-time BC capabilities. Version 2 will incorporate a sampling wheel and otpics to allow near real-time measurements of BC and will include development of a base unit that will operate as a battery re-charger and wireless data teleport, permitting continuous monitoring for up to a month without maintenance. To assess subject compliance, a button-size compliance/location sensor will also be built and tested at this stage. In Version 3 we will test the concept of incorporating ozone detection in near real-time on the third channel,. Solar powered and/or large-battery-powered base units will also be designed for use in settings where access to the power grid is limited, such as in developing countries or for use at fixed-site outdoor locations lacking power. Laboratory and field experiments will be carried out iteratively during development to generate sensor algorithms, find improvements as well as estimate precision and accuracy via comparison to traditional real-time and integrative sampling methods of PM. The final smart air pollution monitor will incorporate upgrades suggested by the latest field-testing.